Monday, February 27, 2017

Today, more than 20 years after of SHA-1 was first introduced, we are announcing the first practical technique for generating a collision. This represents the culmination of two years of research ... As a proof of the attack, we are releasing two PDFs that have identical SHA-1 hashes but different content. ...

Today, more than 20 years after of SHA-1 was first introduced, we are announcing the first practical technique for generating a collision. This represents the culmination of two years of research that sprung from a collaboration between the CWI Institute in Amsterdam and Google. We’ve summarized how we went about generating a collision below. As a proof of the attack, we are releasing two PDFs that have identical SHA-1 hashes but different content.

The attack used 1019 SHA-1 compressions, and is not really a practical attack on the vast majority of the uses of SHA-1.

SHA-1 was phased out of high-security applications about ten years ago.

It is a little odd that Google is so eager to destroy SHA-1. It is also spending tens of millions of dollars to build a quantum computer to destroy RSA cryptography. It is almost as if it wants to wreck everyone security so it can spy on us more easily and sell ads for more money.

This research only applies to situations where you are uniquely identifying a document by its SHA-1 value. If you are hashing documents you produce yourself, it is not really a problem.

Sunday, February 12, 2017

“I said, ‘Raymond, isn’t it true that you’re more intelligent than most people?’ ” Mr. Kotik said during a phone interview. “ ‘Yes,’ he said. So I said, ‘I think that’s unfair. We should take out part of your brain and distribute it to people who could use it.’

“He was silent for a minute, and finally he said, ‘I can’t give you any reason, but I wouldn’t do it.’ ”

Funny. Yes, there are limits to academic leftist egalitarianism. He just cannot articulate a reason for it.

Friday, February 10, 2017

Mathematical research is clearly an international activity. But actually a stronger claim is true: mathematical research is a transnational activity, in that the specific nationality of individual members of a research team or research community are (or should be) of no appreciable significance for the purpose of advancing mathematics. ...

With the recent and highly publicised executive order on immigration, many of these fundamental assumptions have been seriously damaged, if not destroyed altogether. ... This is already affecting upcoming or ongoing mathematical conferences or programs in the US, with many international speakers (including those from countries not directly affected by the order) now cancelling their visit, either in protest or in concern about their ability to freely enter and leave the country. ...

Of course, the impact of this executive order is far, far broader than just its effect on mathematicians and mathematical research.

His post has dozens of comments agreeing with him.

I kept looking for some sign of tangible harm, but skipping a conference in order to protest President Trump is not.

For instance, right now I am at MSRI, together with about a hundred other mathematicians, for semester-long programs in Analytic Number Theory and in Harmonic Analysis. ...

It was already a painful decision for us as organisers to turn away many qualified applicants due to lack of space; in the future the problem will be exacerbated by applicants being unable or unwilling to attend due to travel uncertainties that did not previously exist. ...

Such opportunities may now be denied to many promising young mathematicians, simply by accident of their country of origin.

So Tao is having a wonderful at a USA tax-funded research facility, and qualified Americans are being turned away in favor of mathematicians from hostile Moslem countries.

Tao's argument doesn't even make any sense. If fewer mathematicians can come due to visa difficulties, then that would reduce to need to reject qualified applicants.

Every position offered to a Syrian means one more rejection to a qualified American.

I understand that Tao may have no loyalties to America or to those who pay his 6-figure salary. And if Donald Trump were not the President then he would not have to listen to his fellow professors complain about him. That is about all I get out of his post. American mathematics is not dependent on visas from the 7 hostile Moslem countries.

American mathematics would probably be much healthier if American post-docs and others had better opportunities, instead of facing a system that rewards foreigners. If those Iranian mathematicians are so great, maybe they can stay in Iran and persuade their govt to stop trying to make bombs and support terrorists.

A comment says:

Council of the Australian Mathematical Society wishes to express their support ...

We are concerned in principle about any discrimination that interferes with the free exchange of mathematical ideas across borders.

No one is interfering with sending mathematical ideas across borders. Just use email!

There will not be any objective evidence of any travel ban (if enforced) on mathematics production. Maybe Americans will get better educations because their professors will speak English.

Mathematicians like Tao have been brainwashed by far-left anti-American interests. He is just lying when he pretends that Trump's order is going to cause mathematics to suffer.

Wednesday, February 8, 2017

The NY Times runs anti-Trump articles every day, and now the science section reports:

In Age of Trump, Scientists Show Signs of a Political Pulse

Michael Eisen, an evolutionary biologist, is among the elite of American scientists, with a tenured position at the University of California, Berkeley, and generous funding from the Howard Hughes Medical Institute for his research on fruit flies.

But late last month, dismayed over the Trump administration’s apparent disdain for evidence on climate change and other issues, Dr. Eisen registered the Twitter handle @SenatorPhD and declared his intention to run in the 2018 election for a seat in the United States Senate from California. His campaign slogan: “Liberty, Equality, Reality.”

Why is it that an evolutionary biologist can spend his career studying fruit flies, and suddenly think that he is an expert on climate change?

This seems to be a disease among evolutionary biologists, that they are eager to jump into political disputes way outside their expertise.

Chanda Prescod-Weinstein, a cosmologist and particle physicist at the University of Washington,... said she was especially incensed by what she and others viewed as efforts by some science organizations to reach out to the Trump administration. ...

“What history has taught us is that collaboration doesn’t work for science,” Dr. Prescod-Weinstein said. “When we work with extremist, racist, Islamophobic or nationalist governments, it doesn’t work for science.”

Huhh?

Almost every government that has accomplishment anything in the history of science was what would now be classified Islamophobic and nationalist.

Monday, February 6, 2017

During most of the 20th century, fundamental physics was perceived as a scientific field where theories typically could be empirically tested within a reasonable time frame. ...

Today, the situation is very different. String theory has been playing the role of a well established approach towards a universal theory of all interactions for over three decades and is trusted to a high degree by many of its exponents in the absence of either empirical confirmation or even a full understanding of what the theory amounts to. Cosmic inflation is being trusted by many theoreticians to a degree that in the eyes of many others goes substantially beyond what is merited by the supporting empirical data. Multiverse scenarios in the eyes of critics raise the question to what degree they can be endorsed as scientific hypotheses at all, given that their core empirical implications to a large extent seem not empirically testable in principle. What is at stake here is the understanding physicists have of the status of the theory they work on throughout their lifetimes. In the most far-reaching cases it is the status a given theory can acquire at all.

He is right that there are now hundreds of high-status seemingly-productive physicists who can spend their whole lives publishing papers on ideas that will never see any empirical tests.

Mathematicians never see their ideas empirically tested, but they prove their results, and so they know if they are correct or not. These physicists do not prove anything and never learn whether their ideas have any validity or not. For many of them, it is not clear whether it even makes any sense to say that the ideas have any validity.

Dawid tries to defend the notion that a theory can be confirmed if it is viable, without any evidence that it is true. He claims that there are three ways of doing that:

NAA: The No Alternatives Argument: Scientists have looked intensely and for a considerable time for alternatives to a known theory H that can solve a given scientific problem but haven’t found any. This observation is taken as an indication of the viability of theory H.

MIA: The Meta-Inductive Argument from success in the research field: Theories in the research field that satisfy a given set of conditions have shown a tendency of being viable in the past. This observation is taken to increase the probability that a new theory H that also satisfies those conditions is also viable.

UEA: The Argument of Unexpected Explanatory Interconnections: Theory H was developed in order to solve a specific problem. Once H was developed, physicists found that H also provides explanations with respect to a range of problems which to solve was not the initial aim of developing the theory. This observation is taken as an indication of the theory’s viability.

His best example is string theory. It passes NAA because the alternatives for quantum gravity, MIA because unified field theories have previously been successful, and UEA because it is mathematically interesting.

I say this is crazy, and quantum gravity is not even a scientific problem.

This is just another of how modern philosophers have abandoned truth. They just hate any philosophies that are based on truth.

Atheism is not a belief system ... Everything in the universe was once crunched into something smaller than an atom. ... Science is constantly proved all the time.

There must be some belief system that is telling him that the universe was once smaller than an atom. I would not call that science. We have good theory and evidence for the universe expanding, and it is reasonable to say it was once much smaller. But we cannot go back to the size of an atom. We don't have either the theory or the evidence for that.

I used to accept what he said about atheist not being a belief system. But most self-proclaimed atheists have an assortment of odd unsupported beliefs.

Even though all rational people know that determinism rules human behavior, and in that sense there is no possibility of “choosing otherwise” at a moment of decision — absent quantum effects, which don’t in any way give us “free will” — this conclusion disturbs some people. Our sense of agency is so strong that it’s impossible for many of us to accept determinism of our behavior, or, if we do, to fully grasp its implications.

He is entitled to his opinion, and he may be right that he has no free will. He has written a lot on this subject, so he adequately explains himself. My quarrel here is his belief that "all rational people" agree with him. This is something that leftist atheists say. No, most rational people certainly do not agree with him.

Friday, February 3, 2017

We know general relativity. We know quantum mechanics. What keeps together protons in atoms? What keeps together protons of quarks? These are well-defined properties. Quantum gravity — it’s the concrete stuff. What happens in the center of a black hole? Nobody knows what happens. Why? Because gravity becomes quantum. What happened in the very, very beginning of the universe? Nobody knows because gravity was quantum there. So we need a quantum theory of gravity. It’s not driven by big dreams. It’s driven by specific physical problems and specific inconsistencies in a set of theories that work well.

No, that is not correct. Nobody knows what happens in the center of a black hole because the center is not observable. Likewise for that "very, very beginning of the universe".

this is some sort of modern theology where the high priests want to tell us what happens in Hell or the Astral plane. It might be entertaining, but it has little or nothing to do with science.

Thursday, February 2, 2017

First ever blueprint unveiled to construct a large scale quantum computer

Prof Winfried Hensinger (2), head of Ion Quantum Technology Group (3) at the University of Sussex, who has been leading this research, said: "For many years, people said that it was completely impossible to construct an actual quantum computer. With our work we have not only shown that it can be done but now we are delivering a nuts and bolts construction plan to build an actual large-scale machine."

I haven't read the paper, so I will hold back criticism for now.

At least he concedes that many ppl (besides me) have argued that quantum computers are impossible. Some in the field pretend that they are a consequence of quantum mechanics that everyone accepts.

And he admits that no one has built a quantum computer yet. He just has a detailed plan to build one. Good luck with that. I still say that he will not succeed.

As a next step, the team will construct a prototype quantum computer, based on this design, at the University, and say it could be operational within two years.

'It is the Holy Grail of science, really, to build a quantum computer,' Hensinger told The independent.

'Life will change completely. We will be able to do certain things we could never even dream of before.'

Once built, researchers say the computer's capabilities mean it 'would have the potential to answer many questions in science; create new, lifesaving medicines; solve the most mind-boggling scientific problems; unravel the yet unknown mysteries of the furthest reaches of deepest space; and solve some problems that an ordinary computer would take billions of years to compute.'

This is like a smallpox researcher who is all excited about a new genetically engineered strain of a disease that could soon be unleashed. Exciting for the researcher, and changing life for the worse. The utility of a quantum computer is almost entirely malevolent.

Update: A reader asks:

why would anyone put their career on the line for a project that will ruin them if it turns out to be a scam?

I see a couple of possibilities. One is that he is under increasing pressure from funding agencies. Another is that it is an attempt to get new funding for a bigger project.

Maybe he is a true believer, and wants a piece of the Nobel Prize that goes to the first person to demonstrate quantum supremacy.

And maybe failure will not ruin him anyway. Prominent recent physics failures include supersymmetry, proton decay, string theory, and inflation, but I have not heard of any careers being ruining over these.

Wednesday, February 1, 2017

Minkowski had created the full-blown four-dimensional mathematical formalism of spacetime physics before the end of 1907 (which could have been highly improbable if Minkowski had not been developing his own ideas), both indicate that Minkowski might have arrived at the notion of spacetime independently of Poincare (who saw it as nothing more than a mathematical space) and at a deeper understanding of the basic ideas of special relativity (which Einstein merely postulated) independently of Einstein. So, had he lived longer, Minkowski might have employed successfully his program of regarding four-dimensional physics as spacetime geometry to gravitation as well. Moreover, Hilbert (Minkowski's closest colleague and friend) had derived the equations of general relativity simultaneously with Einstein.

Apparently Max Born credited Minkowski with discovering special relativity independently of Einstein's work.

Minkowski's version was deeper because he had a fully 4-dimensional spacetime view with Maxwell's equations being covariant under the Lorentz group. Einstein's view was similar to Lorentz's.

It is strange to say that Poincare saw spacetime as nothing more than a mathematical space.

In order to understand better what Minkowski could have done, had he lived longer, it is important to take explicitly into account two indications of why he appears to have realized independently the equivalence of the times of inertial observers in relative motion (what Einstein postulated and which formed the basis of his special relativity) and that the Lorentz transformations can be regarded as rotations in a four-dimensional world (which was first published by Poincare but he did not see anything revolutionary in that observation since he believed that physical theories do not necessarily represent anything in the physical world since they are nothing more than convinient descriptions of physical phenomena).

I understand concluding that Minkowski had a much deeper understanding of relativity than Einstein, and would have gone farther if he had lived. But what is this cheap shot at Poincare?

Poincare also wrote about his philosophy of science, and understood that we could have two mathematically equivalent theories for the same physical phenomenon. One theory might be more convenient than the other. He was completely correct about this.

Somehow Petrov (and others) want to turn this around to say Poincare was just a mathematician doing convenient mathematics, and not physics. They say this as if it were possible for Poincare to get all the mathematics of relativity right without understanding the physics. Weird. It is hard to see how anyone could misunderstand the math and philosophy of Poincare so badly.

Minkowski's first paper on relativity did cite Poincare's long famous 1905 paper. It appears to me that Minkowski was strongly influenced by Poincare, but I guess it is possible that Minkowski came to some of the ideas independently.